The present invention relates to conveyor ovens for continuously baking food products, and more particularly, to a tunnel-type conveyor oven having two types of heat sources for more efficient baking of the food products.
Tunnel-type ovens or kilns which are used in connection with commercial baking systems are generally known. The size and type of oven sections used in such commercial baking operations vary depending upon the types of products being produced and the quantity desired. The desired product texture, color and flavor play an important role in defining the type of oven sections used. For instance, radiant heat is used to raise a product's temperature without over drying, and can also provide a toasting effect when radiation is high enough. This allows control of the level of the product's moisture content which is important to the product's texture. Convection heating is used in to provide a balanced heat transfer and a uniform temperature for the product in the oven chamber. While some ovens are known which provide various types of heat, such as radiant oven sections and/or radiant/convection oven sections, it would be desirable to have the ability to provide adjustment to the types of heat being used in a single baking system to allow the most flexibility for producing different types of products.
In one known oven which is designed for use in high volume restaurant operations, such as for baking pizza, a tunnel-type conveyor oven is provided which includes forced hot air convection heat along with infrared strip heaters so that convective and radiant heating take place simultaneously. The heat inputs for convective and radiant heating are independently controlled. The infrared strip heaters each include a porous ceramic element burner which extends from a common side of the conveyor across the conveyor width. Convection heat ducts are located between the infrared strip heaters. The radiant burners are used in conjunction with ceramic plates or tiles which are heated by flames produced by the burners in order to produce radiant heat. The convection heater draws air from within the oven, as well as additional outside air, which is heated by an auxiliary burner and distributed through separate plenums located above and below the conveyor which extends through the tunnel oven.
It would be desirable to provide a combination radiant/convection tunnel oven which provides uniform heating across the width of the conveyor and which offers the flexibility of changing the ratio of radiant and convective heat that the product experiences.